ResampleAudio

High-quality audio sample rate converter:

• Accepts any number of channels.

• The conversion is skipped if the sample rate is already at the given rate.

• Supports fractional resampling (where new_rate_denominator ≠ 1).

• Note, internal rounding may affect AudioDuration slightly – see Examples below.

See Wikipedia: Sample-rate conversion

Syntax and Parameters

ResampleAudio (clip, int new_rate_numerator, int "new_rate_denominator")

clip

Source clip. Supported audio sample types: 16-bit integer and 32-bit float.

Other sample types (8-, 24- and 32-bit integer) are automatically converted to 32-bit float.

new_rate_numerator

Set the numerator for the new sample rate.

new_rate_denominator

Set the denominator for the new sample rate.

Default: 1

Examples

• Resample audio to 48 kHz:

  source = AviSource("c:\audio.wav")
  return ResampleAudio(source, 48000)
  

• Exact 4% speed up for Pal telecine:

  nfr_num = 25
  nfr_den = 1
  AviSource("C:\Film.avi") # 23.976 fps, 44100Hz
  ar = Audiorate()
  # intermediate sample rate:
  ResampleAudio(ar*FramerateNumerator*nfr_den, FramerateDenominator*nfr_num)
  # final sample rate:
  AssumeSampleRate(ar)
  AssumeFPS(nfr_num, nfr_den, sync_audio=False)
  

In the example above, the intermediate sample rate needs to be:

(AudioRate*FramerateNumerator*nfr_den=1)/(FramerateDenominator*nfr_num=25)

or (44100 * 24000 * 1) / (1001 * 25) = 42293.706294...

But because audio sample rates are always integers, 42293.706294 must be rounded to 42294, which results in a time slippage of about 30ms per hour.

Changelog

Version	Changes
AviSynth 2.5.6	Added Float support in ResampleAudio(). Added Fractional resampling support in ResampleAudio().
AviSynth 2.5.3	ResampleAudio now accepts any number of channels.

$Date: 2022/02/13 11:10:51 $